Harold was played by actor Tom Troupe. It was not known if he was the only survivor; CaptainJames T. Kirk did not think this to be the case for before he left in pursuit of the Gorn vessel, he left thirty medical personnel behind on the planet on a search and rescue mission for survivors.

The final draft script of "Arena" described Harold as a lieutenant, a rank which Kirk too – in both the script and the actual episode – identified him as. Although Kirk addressed him as "lieutenant" only once in the episode, however, the script included three occasions on which the captain did so and another time on which Dr.McCoy did likewise. These references were despite the fact that no rank braids were present on Harold's uniform. His clothing was a rare black-collared variant of the beige operations division uniform style, also seen on CommanderHansen in TOS: "Balance of Terror". Harold's name was given in the credits and final draft script only. The script additionally referred to him as a communications officer, describing the rubble amid which he was discovered as the remains of his communications equipment.